The present invention relates to a ventilating arrangement, particularly an air conditioning arrangement for a vehicle. More particularly, it relates to a ventilating or air conditioning arrangement which has an air passage with an adjustable flow regulating flap, an impeller rotatable with a variable rotary speed, and a pressure measuring element which acts upon the flow regulating flap and changes the rotary speed of the impeller so that, despite differing travel speeds, an air throughput quantity adjusted on a nominal value setter remains substantially the same.
An arrangement of the above mentioned general type is disclosed, for example, in U.S. Pat. No. 3,845,700. In this arrangement an air passage leads from outside into the passage or cabin of the vehicle, a flow regulating flap is built in the air passage, and an impeller driven by an electric motor is also provided. A venturi nozzle is arranged in the front part of the car, and a bellows is connected with the venturi nozzle. It measures the pressure outgoing from the venturi nozzle and acts via a rod onto the regulating flap and a regulating resistance arranged prior to the electric motor. This rod is formed so that, starting from its position with immovable vehicles in which the regulating resistance is bridged and the flow regulating flap is maximum opened, it increasingly connects in a first movement region with constantly open flap the regulating resistance to the current supply of the electric motor. When the regulating resistance is completely turned on, the rod is retained rigid relative to the flow regulating flap so that in the subsequent moving region with increasing vehicle speed the flap is progressively closed. This ventilating arrangement retains the air throughput substantially constant. The air throughput is selected manually with the aid of a threaded spindle which changes the length of the rod. The disadvantage of this construction is that the venturi nozzle is remote from the inlet of the air passage. Such an arrangement is not implemented in the vehicle industry. Moreover, further difficulties are expected when a water cooler for the motor is arranged in the vehicle in the vicinity of the venturi nozzle, and a cooling ventilator with an arbitrarily variable rotary speed is provided. The turning on or turning off, or the variation of the rotary speed of the ventilator influences the inflow speed of air in the front part of the vehicle. For attaining a sufficiently accurate adjustment of the regulating flap, the bellows must be formed voluminously, which makes difficult its placement in the vehicle.
U.S. Pat. No. 3,587,439 discloses also such a ventilating arrangement with a bellows and uses an electric driving element for the regulating flap.